Communication apparatus preventing communication interference

ABSTRACT

A game apparatus according to a preferred embodiment includes a first wireless communication module and a second wireless communication module. The first wireless communication module performs communication utilizing Bluetooth protocols, whereas the second wireless communication module performs communication utilizing IEEE protocols. The first radio communication module and the second radio module have a common reference communication cycle, and each communicates in communication cycles of an integral multiple of the reference communication cycle. A control unit sets offset time between the start time of a communication by the first wireless communication module until the start time of a communication by the second wireless communication module. In so doing, the control unit monitors the communication load of the first wireless communication module and sets the offset time based on a monitored result.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to radio communication apparatuses withwireless communication functions, and it particularly relates to acommunication terminal apparatus equipped with a plurality ofcommunication modules.

2. Description of the Related Art

In recent years, a variety of wireless communication protocols have beenproposed and put to practical use. Representative of such protocoltechnologies are the widedband wireless local area network system (WLAN)standardized by the IEEE 802.11 and the wireless communicationtechnology for mobile information devices (e.g., Bluetooth: registeredtrademark) standardized by the IEEE802.15.1. Incorporated into diverseinformation terminal apparatuses, such technologies are used in wirelessconnection with peripheral devices, such as PDAs (personal digitalassistants), printers and headsets. Owing to the technologicalinnovation of recent years, wireless communication modules today aremanufactured small and inexpensive, and it is also possible to buildmodules employing multiple types of wireless communication protocolsinto a single device or casing.

A wireless communication module must be able to transmit signals for acertain distance, receive weak radio waves transmitted by a peripheraldevice and reproduce signals therefrom. Accordingly, a wirelesscommunication module is structured by a transmitter capable of highoutput and a receiver with high sensitivity.

If a plurality of wireless communication modules are built into a singledevice or casing, those wireless communication modules will be placed inclose proximity to one another because of the limited space. As anatural consequence, mutual interference of radio waves occurs among thewireless communication modules themselves. In particular, the problem ofmutual interference can be pronounced between a wireless communicationprotocol defined by the IEEE 802.11 (hereinafter referred to as “WLAN”or “WLAN protocol”) and a wireless communication protocol defined by theIEEE 802.15.1 (hereinafter referred to as “Bluetooth” or “Bluetoothprotocol”), both of which use the same 2.4 GHz band.

A technology developed for the Bluetooth protocol to avoid interferenceamong different wireless communication modules is called AFH (AdaptiveFrequency Hopping). The AFH technology stabilizes communication underthe Bluetooth protocols by frequency hopping, in which a Bluetoothcommunication module avoids the use of the frequency bands occupied bythe other communication modules in the same range of frequency and usesonly usable frequencies for communication.

However, when a plurality of wireless communication modules are builtinto a single device or casing, those wireless communication modulesmust be placed in close proximity to one another. Thus, thecountermeasure by AFH alone cannot sufficiently eliminate the mutualinterference of radio waves therebetween. Especially when a wirelesscommunication module is in a transmission mode and at the same timeanother adjacent wireless communication module is in a reception mode,the latter cannot avoid receiving the high-output transmission wavesoutputted by the former in close vicinity. Consequently, the signals tobe received primarily may get buried in the received radio waves, thuscreating a situation where necessary signals cannot be reproducedproperly. Therefore, it is strongly desired that a technology bedeveloped that can realize a stable communication when a plurality ofwireless communication modules are built into a single device or casing.

SUMMARY OF THE INVENTION

In order to solve the above problems, a communication terminal apparatusaccording to a preferred embodiment of the present invention comprises:a first wireless communication module; a second wireless communicationmodule; and a control unit. The first wireless communication moduleexecutes communication in a predetermined frequency band, using a firstcommunication scheme. The second wireless communication module executescommunication in the predetermined band, using a second communicationscheme that differs from the first communication scheme. The controlunit has said first wireless communication module and said secondwireless communication module, respectively, execute communication inaccordance with a common reference communication cycle. The control unitmay set, to the second wireless communication module, a communicationprohibited period in each reference communication cycle. Moreover, acommunication cycle in the first wireless communication module and thesecond wireless communication module may be set to an integral multipleof a reference communication cycle.

According to this embodiment, a communication duration is reliablysecured for the first wireless communication module by disablingcommunication by the second wireless communication module. In otherwords, the execution of communication by the second wirelesscommunication module is prohibited during the period in which the firstwireless communication module is executing a communication. Thus, astate in which one communication is not interfered with anothercommunication can be created.

It is to be noted that any arbitrary combination of the above-describedstructural components and expressions changed among a method, anapparatus, a system, a recording medium, a computer program and so forthare all effective as and encompassed by the present embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described by way of examples only, withreference to the accompanying drawings which are meant to be exemplary,not limiting and wherein like elements are numbered alike in severalFigures in which:

FIG. 1 illustrates a structure of a communication system according to anembodiment of the present invention.

FIG. 2 is an example of function blocks for a control unit.

FIG. 3 illustrates an example of the structure of a first wirelesscommunication module shown in FIG. 1.

FIG. 4 illustrates an example of the structure of a second wirelesscommunication module shown in FIG. 1.

FIG. 5A shows a state of communication between a first wirelesscommunication module and a radio game-controller;

FIG. 5B shows a state of communication by a second wirelesscommunication module; FIG. 5C shows a period in which a communicationbetween a second wireless communication module and a mobile gamemachine/PC is to be prohibited; and FIG. 5D shows an example of a stateof transmission of BT_Sync transmitted from a first wirelesscommunication module to a second wireless communication module.

FIG. 6A shows a state of communication between a first wirelesscommunication module and a radio game-controller;

and FIG. 6B shows a state of communication between a second wirelesscommunication module and a mobile game machine.

FIG. 7A shows a state of communication between a first wirelesscommunication module and a radio game-controller; and FIG. 7B shows anexample of an interval where a communication by a second wirelesscommunication module is prohibited.

DETAILED DESCRIPTION OF THE INVENTION

The terms and description used in defining the preferred embodiments ofthe present invention to be taken with the accompanying drawings are setforth for the purposes of clarification and illustration only. Thepresent invention described herein are not meant as limitations but areto be understood to include all the equivalent technologies that areimplemented for the similar purpose under the similar rules.

Before describing the present invention in detail, an outline of thepresent invention will be described first. A communication systemaccording to an embodiment of the present invention includes a gameapparatus which includes two wireless communication modules in a singledevice or casing and a controller which instructs the game apparatus.The two wireless communication modules use each the same frequency band.For example, one of the two wireless communication modules performscommunication, by Bluetooth, with a controller that gives instructionsto a game apparatus or the like. The other thereof performscommunication, by WLAN, with a mobile game machine or the like which maybe equivalent to a PC or controller. In such a case, in order to preventcross talk between them and also to avoid interference by the other, thecommunication execution in the two wireless communication modules needsto be properly scheduled in terms of timing. Though “scheduling” may bedefined by various modes, the description will be herein given of aperiodic scheduling.

A periodic scheduling is accomplished, as a general rule, by executingeither one of Bluetooth communication and WLAN communication in a givencommunication period. However, where a communication period is setfixedly, there are cases where one of the communications must be put onstandby until the arrival of the next communication period even when alonger execution time therefor is desired within a communication period.For example, when a game participated simultaneously by a plurality ofpeople is being played, a new person who wants to join the game maysuffer an inconvenience of being unable to join in it right away. Anynew participation in a game cannot be anticipated because it isaccomplished by the operation of a controller by the decision of theuser. There is also another problem that if a communication time is setlonger within a communication period after the operation of thecontroller, then smooth participation in the game will be furtherhampered.

Bluetooth communication and WLAN communication generally use the samefrequency band, so that when such communications are executed at thesame time, they interfere with each other. Also, the protocol forBluetooth communication is less flexible than the protocol for WLANcommunication. According to the present embodiment, therefore,interference is avoided with a WLAN wireless communication modulecarrying out a scheduling semiautonomously by grasping the state ofcommunication by a Bluetooth wireless communication module. To grasp thestate of communication of a Bluetooth wireless communication module, theBluetooth wireless communication module may send or convey a signal,such as a pulse signal or a synchronous signal, which shows the state ofcommunication thereof, to the WLAN wireless communication module. Then,based on the state of communication of the Bluetooth wirelesscommunication module or the like, the WLAN wireless communication modulesemiautonomously stops a transmission to a portable game and also sendsa signal to have the portable game disable a transmission therefrom.Furthermore, as an arrangement to realize a flexible midwayparticipation by a new user in a game or communication currently goingon, an interval in which the execution of communication by a Bluetoothwireless communication module is protected (hereinafter referred to as“protected period”) is set longer within at least one of a plurality ofcommunication periods. The details of this arrangement will be describedlater.

Employing an embodiment such as this assures the coexistence ofcommunication by Bluetooth and communication by WLAN. Also, even whenthe amount of communication by WLAN is large, the protected period isset longer in certain communication periods, so that the Bluetoothcommunication time can be obtained without fail. Note, however, thatwhile communication by a Bluetooth wireless communication module in theprotected period is guaranteed, it is not always necessary to conduct acommunication in that period. For example, if there is an interval witha smaller amount of communication by WLAN, the Bluetooth wirelesscommunication module can use communication time slots given to the WLANwireless communication module for its own communication. Therefore, thisadditional use of the time slots can further enhance the possibility ofmidway participation by a user in the game.

FIG. 1 illustrates a structure of a communication system 1 according toan embodiment of the present invention. The communication system 1includes a game apparatus 10, radio game-controllers 25 a, 25 b and 25 c(hereinafter referred to as “radio game-controller 25”) for wirelessconnection with the game apparatus 10, mobile game machines 30 a and 30b (hereinafter referred to as “mobile game machine 30”) and a personalcomputer 32 (hereinafter referred to as “PC 32”). The game apparatus 10comprises, in a single device or casing, a first wireless communicationmodule 12 and a second wireless communication module 14, both havingcommunication functions, a control unit 16 which manages the gameapparatus in a controlled manner, an application processing unit 18which executes game applications, and an output unit 20 which outputsthe results of processing a game application. The game apparatus 10,which is provided with the first wireless communication module 12 andthe second wireless communication module 14, functions as a wirelesscommunication terminal apparatus. The first wireless communicationmodule 12 and the second wireless communication module 14 realize theirrespective communications using their respective wireless communicationprotocols or wireless communication schemes in the same frequency band.It is to be noted that the first wireless communication module 12 mayperform its communication with a weaker communication power than that ofthe second wireless communication module 14.

The radio game-controllers 25 in the communication system 1 are gamecontrollers for the game apparatus 10, and one or more users may play agame by operating a radio game-controller 25 or radio game-controllers25 while watching the game screen displayed on the display for the gameapparatus 10. The mobile game machines 30 are terminal apparatuses thatallow a plurality of persons to play a game simultaneously by getting amobile game machine 30 in communication with another mobile game machine30 via the game apparatus 10 serving as a relay station. The mobile gamemachines 30 may also have a function of receiving moving image data fromthe game apparatus 10 and offering the moving images to the users.Moreover, the mobile game machines 30 may be used as game controllersfor the game apparatus 10, and the users may play a game by operatingthe mobile game machines 30 while watching the game screen displayed onthe display for the game apparatus 10. Thus, the game apparatus 10 mayfunction in response to a plurality of intended usages. The control unit16 schedules the execution of communication by the first wirelesscommunication module 12 and the second wireless communication module 14.In an embodiment of scheduling, one mode is selected from a plurality ofpreset modes. Hereinbelow, a detailed description is given of a modethat has communication executed by the first wireless communicationmodule 12 and the second wireless communication module 14 periodically(hereinafter referred to as “periodic mode” or “periodic communicationmode”).

The periodic mode is a mode for avoiding mutual interference betweenWLAN communication and Bluetooth communication, in which a firstwireless communication module 12 and a second wireless communicationmodule 14 are required to perform their respective communications usingthe reference communication cycle common thereto. The periodic mode isalso a mode which may be selected when a user is playing a game using aradio game-controller 25 or a mobile game machine 30 as a controller andat the same time another user desires to use a PC 32. In this case,communication between the game apparatus 10 and the radiogame-controller 25 or the mobile game machine 30 is considered torequire greater real-timeliness than the communication with the PC 32,so that it is necessary to provide a sufficient communication timeand/or communication band for the radio game-controller 25 or the mobilegame machine 30. “Requiring greater real-timeliness” means, amongothers, that retransmission, as a rule, is not assumed or permittedand/or permissible processing delay is small. For example, it means thatwhen a user operates a radio game-controller 25 or a mobile game machine30, he/she does not feel displeasure because all the contents of his/heroperation are communicated to the game apparatus 10, the game apparatus10 executes the contents faithfully, and in addition the execution isreflected fully by the screen display. The Bluetooth protocol used inthe communication with a radio game-controller 25 is often subject tothe difficulty of timing control than the WLAN protocol used in thecommunication with a PC 32. Hence, it is so arranged that the WLANprotocol used in the communication between the PC 32 and the gameapparatus 10 executes the scheduling for communication in considerationof the state of communication between the radio game-controller 25 andthe game apparatus 10. Furthermore, when used as a controller, themobile game machine 30, for which communication is executed by WLANprotocol as with the PC 32, has a higher priority than the PC 32.Accordingly, the arrangement is such that the communication between thePC 32 and the game apparatus 10 is executed after the end ofcommunication between the mobile game machine 30 and the game apparatus10.

Certain types of games may require midway participation by a user orusers after the game has been started. In anticipation of this kind ofsituation, the

WLAN protocol determines an enabled communication interval for thesecond radio communication module 14 to be periodically shorter in orderto provide a sufficient communication time and/or communication band forthe first radio communication module 12, which is to communicate with aradio game-controller 25 participating halfway. In other words, thecontrol unit 16 sets a periodically longer time for the period wherecommunication by the second radio communication module 14 is prohibitedor disabled. The arrangement like this can provide the users with apleasant communication environment and/or game playing environment.Moreover, even when a plurality of users use a plurality of applicationsalmost simultaneously, there will be no interruptions of thecommunication and/or the game. The second wireless communication module14 may operate semiautonomously in such a manner as not to hinder theexecution of communication by the first wireless communication module12, based on the instruction by a parameter sent form the control unit16 and/or the information on the state of communication of the firstwireless communication module 12 sent therefrom. It is to be noted thatthe above-described scheduling may be realized with the control unit 16controlling everything and sending instructions as appropriate to thefirst wireless communication module 12 and the second wirelesscommunication module 14.

In the present embodiment, the first wireless communication module 12enables wireless connection with a plurality of radio game-controllers25 by performing wireless communication under the Bluetooth protocol.Bluetooth employs a frequency-hopping spread spectrum to reduceinterference. In the communication system 1, the first wirelesscommunication module 12 functions as a master to the radiogame-controller 25 and the radio game-controller 25 functions as a slavethereto. A piconet is formed between the first wireless communicationmodule 12 and the radio game-controller 25. A piconet is a networkformed temporarily between Bluetooth terminals when they are placedclose to one another, and a maximum of eight Bluetooth terminals canparticipate in a single piconet. Hence, the first wireless communicationmodule 12 as a master can be wirelessly connected with a maximum ofseven radio game-controllers 25.

The second wireless communication module 14 enables wireless connectionwith a plurality of mobile game machines 30 and a PC 32 by performingwireless communication under the IEEE802.11 protocol. The IEEE802.11protocol to be employed may be IEEE802.11b and/or IEEE802.11g, forinstance. In the communication environment of the IEEE802.11 protocol,the second wireless communication module 14 functions as an accesspoint. In the MAC layer technology of wireless LAN using the IEEE802.11protocol, CSMA/CA (Carrier Sense Multiple Access with CollisionAvoidance) is employed as an access control system, so that theIEEE802.11 terminal has a function of transmitting data only aftermaking certain that the communication channel is free for apredetermined length of time or more. This waiting time, which is thesum of a minimum time and the waiting times of random lengths for therespective terminals, prevents the collision of signals which may occurif a plurality of terminals transmit signals simultaneously a certaintime after an immediately preceding communication.

A description is given here of a case where status information on a gameapplication is communicated between a second wireless communicationmodule 14 and a mobile game machine 30. Data transmission and receptionrelated to the processing of a game application take place among a gameapparatus 10, radio game-controllers 25 and mobile game machines 30 asshown in FIG. 1, so that real-timeliness of information transmissionamong them must be assured to one degree or another. Hence, in thecommunication system 1 according to the present embodiment, thecommunication related to the processing of a game application isstabilized by minimizing the overlapping of the period for communicationby the first wireless communication module 12 and the period forcommunication by the radio game-controllers 25 on the time axis as muchas possible. On the other hand, the communication between the secondwireless communication module 14 and the PC 32, which is not used forthe execution of a game application, does not require strictreal-timeliness. For example, a state of use is assumed in which thegame apparatus 10 is connected to the Internet via a router and the PC32 is transmitting and receiving Email. Accordingly, the communicationbetween the second wireless communication module 14 and the PC 32 iscarried out in the time zone where neither the communication between thefirst wireless communication module 12 and a radio game-controller 25nor the communication between the second wireless communication module14 and a mobile game machine 30 is taking place.

FIG. 2 is an example of a block diagram showing the functions of acontrol unit 16. The control unit 16, having an interface unit 50 abetween itself and a first wireless communication module 12 and a secondwireless communication module 14 and an interface unit 50 b betweenitself and an application processing unit 18, exchanges data with theother structures. The interface unit 50 a and the interface unit 50 bmay have a common hardware structure. The control unit 16 furtherincludes a data transfer unit, a communication load monitoring unit 54,a latency determining unit 56, a communication timing setting unit 58and a clock unit 60. Although the control unit 16 has a function ofperforming an overall control of the game apparatus 10, FIG. 2 shows, inparticular, the function block for controlling the communication of thegame apparatus 10.

The communication controlling functions are realized by a CPU, a memory,a memory-loaded program and the like, but drawn and described herein arefunction blocks that are realized in cooperation with those. Theprograms may be incorporated into a game machine 10 and may be suppliedexternally in a form stored in a recoding medium. Thus, it is understoodby those skilled in the art that these function blocks can be realizedin a variety of forms such as by hardware only, software only or thecombination thereof.

The communication load monitoring unit 54 monitors the respectivecommunication loads of the first wireless communication module 12 andthe second wireless communication module 14. The communication loadmonitoring unit 54 may grasp the respective communication loads of thecommunication modules by monitoring the number of radio game-controllers25 wirelessly connected to the first wireless communication module 12and the number of mobile game machines 30 connected to the secondwireless communication module 14. The communication load monitoring unit54 may monitor the respective communication loads of the first wirelesscommunication module 12 and the second wireless communication module 14periodically. Also, when there is any change in the numbers of unitsconnected thereto, the communication load monitoring unit 54 may monitorthe communication loads by receiving the new numbers of units connectedthereto from the respective wireless communication modules 12 and 14.The communication load monitoring unit 54 sends the results ofmonitoring the respective communication loads of the communicationmodules to the communication timing setting unit 58.

The communication timing setting unit 58 receives the results ofmonitoring the respective communication loads of the first wirelesscommunication module 12 and the second wireless communication module 14and sets parameters respectively for the first wireless communicationmodule 12 and the second wireless communication module 14. Theparameters to be sent from the control unit 16 to the second wirelesscommunication module 14 in the periodic mode may include, at least,“mode information”, “communication cycle”, “communication prohibitedperiod”, and “cycle for communication prohibited period”. “Modeinformation” is an identification information for scheduling the firstwireless communication module 12 and the second wireless communicationmodule 14, and the message to be conveyed herein is the periodiccommunication mode. This message is sent at least to the second wirelesscommunication module 14. “Communication cycle” is a communication cyclefor the first wireless communication module 12 or the second wirelesscommunication module 14, which has an integral multiple length of apredetermined reference communication cycle.

“Communication prohibited period” or “communication suppression period”,which includes a period prohibiting communication by the second wirelesscommunication module 14, is set for each communication cycle. In acommunication prohibited period, a communication duration is reliablysecured for the first wireless communication module 12 by disablingcommunication by the second wireless communication module 14. Also, thecommunication prohibited period may or may not be defined as consecutiveperiods. Where a communication prohibited period is to be set as anonconsecutive duration, the period from the top timing to a firsttiming may be set as a first communication prohibited period, and theperiod from a second timing after the first timing to the end timing ofthe communication period may be set as a second communication prohibitedperiod, for instance. The description hereinbelow assumes that thecommunication prohibited period is a nonconsecutive duration.

The first communication prohibited period may be set based on thecommunication load of the first wireless communication module 12. Forexample, where the first wireless communication module 12 is managingthree radio game-controllers 25, it is necessary that there are a totalof six time slots for polling the respective radio game-controllers 25and receiving the responses therefrom. In this case, the communicationtiming setting unit 58 decides that the time for at least 6 time slotsis necessary for the communication by the first wireless communicationmodule 12 and thus sets the first communication period to the time for 6time slots or more, or preferably the time for 6 time slots. As will bedescribed later, it is preferable that the communication between thefirst wireless communication module 12 and a radio game-controller 25 bedone in a bursty manner so as to facilitate the computation of the firstcommunication period. It is to be noted here that setting an integralmultiple length of a reference communication cycle for each of thecommunication periods can make the relative time difference in the starttime of each of the communication periods constant. By implementing thisarrangement, the first communication prohibited period may, inprinciple, be fixed so long as there is no change in the number ofexternal terminals connected to the first wireless communication module12 and the second wireless communication module 14, and thus thecommunication timing setting unit 58 may determine the firstcommunication prohibited period only once.

Here, the second communication prohibited period includes a duration inwhich the first wireless communication module 12 carries out a page scanof two frequency bands alternately. The second communication prohibitedperiod may also be set with an added time to search for a radiogame-controller 25 which will newly establish a wireless connection withthe first wireless communication module 12. The time to search a newradio game-controller 25 includes the time for the first wirelesscommunication module 12 to “inquire” peripheral communication terminalsabout possible connection and the time therefor to “call” afterrecognizing such a radio game-controller 25. The page scan is carriedout normally during a communication prohibited period by the controlunit 16, when communication between the radio game-controller 25 and thefirst wireless communication module 12 is reliably secured, but may alsobe carried out during a period other than the communication prohibitedperiod. This is because the second wireless communication module 14 isnot always communicating during periods other than a communicationprohibited period. The second communication prohibited period may be setby the control unit 16 to the second wireless communication module 14 atthe rate of once an integral multiple of a reference communication cycleor communication cycle. Here, the page scan by the control unit 16 iscarried out once every communication period alternately for the twofrequency bands. In this case, if the second communication prohibitedperiod is set for a rate of once an even-numbered multiple of areference communication cycle or communication cycle, then the page scanduration for the same one of the frequency bands will always be longer,thus making it impossible to make the page scan duration for the otherfrequency band long. Hence, the second communication prohibited periodshould preferably be set to occur at the rate of once an odd-numberedmultiple of a reference communication cycle or communication period.Note also that the page scan includes, among others, the search by thefirst wireless communication module 12 for a radio game-controller 25that is about to start a communication using the Bluetooth protocol.Such an arrangement provides the user with a pleasant operationenvironment.

The second wireless communication module 14 executes a communicationusing the CSMA/CA scheme, so that it is not easy to determine anaccurate time from the start to the end of the communication. Hence, itis preferable that the communication timing setting unit 58 predicts thetime from the start to the end of communication by the number of mobilegame machines 30 being controlled by the second wireless communicationmodule 14 and then sets a second communication period by adding acertain time margin to the predicted time. The communication timingsetting unit 58 set parameters in such a manner as to avoid theoverlapping of communications by the first wireless communication module12 and the second wireless communication module 14. It is to be notedthat a communication prohibited period is normally shorter than acommunication cycle. Accordingly, when the sum of the execution periodsof communication by the first wireless communication module 12 and thesecond wireless communication module 14 is larger than M times (M aninteger greater than or equal to 1)and not more than (M+1) times thereference communication cycle, the communication timing setting unit 58sets each of the communication period of the first wirelesscommunication module 12 and the communication period of the secondwireless communication module 14 to (M+1) times the referencecommunication cycle or more. This arrangement can create a conditionwhere there is no overlapping of the communications by the firstwireless communication module 12 and the second wireless communicationmodule 14.

Setting the communication prohibited period like this can not onlyreliably secure the communication time for the first wirelesscommunication module 12 but also improve the throughput ofcommunication. It should be noted here that the first wirelesscommunication module 12, as a rule, executes communication during acommunication prohibited period, when the second wireless communicationmodule 14 is not communicating, but may also execute communicationduring a period other than the communication prohibited period. This isbecause the second wireless communication module 14 is not necessarilyalways communicating during periods other than a communicationprohibited period and thus there are possibilities that the firstwireless communication module 12 can execute communication. In such acase, the first wireless communication module 12 may not always be ableto execute communication, but the throughput can be further enhanced ifretransmission control or the like is combined.

“Cycle for communication prohibited period” means a cycle to which asecond communication prohibited period is applied. For example, “3” forthe cycles for communication prohibited period means that in one of thethree communication periods, a second communication prohibited period isset together with a first communication prohibited period while a firstcommunication prohibited period only is set in the other twocommunication cycles. Preferably, a communication prohibited period maybe set at a rate of every odd-numbered times of a communication cycle ora reference communication cycle.

The parameters to be sent from the control unit 16 to the first wirelesscommunication module 12 in the periodic communication mode include“start timing of communication cycle”. The first wireless communicationmodule 12 sends a pulse information indicative of the start timing of acommunication period (hereinafter denoted by “BT_Sync”) to the secondwireless communication module 14, based on the start timing of thecommunication cycle. Using the BT_Sync sent therefrom, the secondwireless communication module 14 derives the start timing of a firstcommunication prohibited period. In other words, BT_Sync makes itpossible for the second wireless communication module 14 to cause amobile game machine 30 or a PC 32, which is the other communicationparty, to stop communicating and to find the duration in which thesecond wireless communication module 14 itself has to stopcommunicating. Employing an arrangement like this according to thepresent embodiment enables processings synchronized between the firstwireless communication module 12 and the second wireless communicationmodule 14. Moreover, the second wireless communication module 14, whichcan find the period in which the second wireless communication module 14itself has to stop communicating, can autonomously reduce or eliminatethe mutual interference of radio waves between the wirelesscommunication modules, thus realizing a game apparatus 10 that providesstable communication.

As previously described, in a game apparatus 10 according to the presentembodiment, the first wireless communication module 12 and the secondwireless communication module 14 have a reference communication cyclecommon thereto. In the first wireless communication module 12, which isa Bluetooth master, the reference communication cycle is set to theminimum interval of polling, which individually calls the radiogame-controllers 25 at every operation during the intermittent operationin a sniff mode. On the other hand, in the second wireless communicationmodule 14, the reference communication cycle is set as the minimumbeacon interval under the IEEE802.11 protocol. With a game apparatus 10according to the present embodiment, the results of processing by theapplication processing unit 18 are outputted as moving images by theoutput unit 20, and accordingly the reference communication cycle isset, for instance, to 11.25 msec if it is necessary to assure one timeof communication of each terminal with the game apparatus 10 within aframe based on the frame rate of the moving images.

The communication timing setting unit 58 sets the respectivecommunication periods for the first wireless communication module 12 andthe second wireless communication module 14 to certain integralmultiples of the reference communication cycle. The first wirelesscommunication module 12 and the second wireless communication module 14communicate with their respective external terminals at thecommunication periods, which are integral multiples of the referencecommunication cycle, by repeating their respective communication statesand noncommunication states alternately. Since the respectivecommunication starting times of the first wireless communication module12 and the second wireless communication module 14 are equal to thestarting times of their respective communication cycles, communicationswith the external equipment will start together with the starts of thecommunication cycles. In this present specification, the communicationcycles of the second wireless communication module 14 is thecommunication cycle used in the communication between the secondwireless communication module 14 and a mobile game machine 30. Asdiscussed earlier, the communication between the second wirelesscommunication module 14 and a PC 32 takes place, using free time thatmay be present. Note that when there is no communication between thesecond wireless communication module 14 and the PC 32 during this freerun time, the first wireless communication module 12 may search for aradio game-controller with which to establish a new wireless connection.

The data transfer unit 52 transmits operation inputs received by theinterface unit 50 a to the application processing unit 18 from theinterface unit 50 b. The application processing unit 18 performsprocessings according to the operation inputs, which cause the game toprogress.

From the viewpoint of requirement for real-timeliness, the gameapplications can be roughly classified into two groups, namely, onesrequiring higher real-timeliness and ones requiring lowerreal-timeliness. The games requiring higher real-timeliness are, forexample, battle games or racing games, which are fast-progressing andthus require the operation inputs by the users to be reflected quicklyin the game screen or other outputs. On the other hand, the gamesrequiring lower real-timeliness are, for example, the match-up gamessuch as shogi (Japanese chess) and mahjong, as well as RPGs(roll-playing games), whose progress is relatively slow.

The updating of a game screen is done at a predetermined frame rate orrefresh rate. The rewrite speed for one field at the current stage is16.7 msec (1/60 sec). Therefore, with a game application requiring highreal-timeliness, namely, minimal delay or low delay, it is desirablethat the operation inputs from the radio game-controllers 25 bereflected on the game screen at least once per field (16.7 msec).

The same thing can be said for a mobile game machine 30 which uses thesecond wireless communication module 14 as the access point. That is, itis desirable that the mobile game machine 30 communicate its own statusinformation to the other mobile game machines 30 and find out about thestatus information of the other mobile game machines 30 at least onceper field. The status information in a racing game, for instance, aresuch absolute information as the position on the course and thedirection and speed of the racing car. It is to be noted that the use ofabsolute information here is on account of the less than adequatereliability of communication in the wireless environment, and thereforeif a sufficient reliability can be obtained, knowing the differenceinformation between the past and the present will suffice to achieve anintended result.

In the communication system 1 as shown in FIG. 1, each of the mobilegame machines 30 executes an application independently andasynchronously. It is to be noted that for game applications that do notrequire low delay or low latency, this does not produce any significanteffect on the processing of such applications because retransmissionprocessing can be used even when the data update cannot be done in eachfield.

In view of the aforementioned circumstances, the latency determiningunit 56 monitors, via the interface unit 50 b, the progress of gameprocessed in the application processing unit 18 and then determines thedegree of latency. The above indicates the latency required by the radiogame-controller 25. However, the same thing can be said of the mobilegame machine 30, and the latency determining unit 56 monitors, via theinterface unit 50 b, the progress of game in the mobile game machine 30so as to determine the degree of latency required by the mobile gamemachine 30. The latency determining unit 56 transmits the determineddegree of latency to the communication timing setting unit 58.Hereinbelow, the degree of latency required by the radio game-controller25 will be discussed and examined.

If the low-delay is required of the radio game-controller 25, thecommunication timing setting unit 58 sets shorter the communicationcycle of the first wireless communication module 12. As describedearlier, the communication cycle of the first wireless communicationmodule 12 is set to an integral multiple of a reference communicationcycle (11.25 msec). Hence, the communication cycle is set to the minimumduration of a reference communication cycle which is 11.25 msec×1. If,on the other hand, no low-delay is required of the radio game-controller25, that is, if the real-timeliness required in the progress of game islow, the communication cycle may be set to P times the referencecommunication cycle (P being an integer greater than or equal to 2). Ifthe required real-timeliness is low, the power consumed by the radiogame-controller 25 can be restricted by setting longer the communicationcycle of the first wireless communication module 12. In this case, it ispossible to set longer the second communication period for the secondwireless communication module 14. It is also assumed that the secondwireless communication module 14 transmits video data to the mobile gamemachine 30, so that the communication efficiency of a game apparatus asa whole can be improved by setting shorter a period during which thefirst communication module 12 is active.

FIG. 3 illustrates an constitutional example of the first wirelesscommunication module 12 shown in FIG. 1. The first wirelesscommunication module 12 includes a first parameter processing unit 44, afirst transceiver 46, an operational state notifying unit 48 and asynchronous signal notifying unit 62. The first transceiver 46 receivesoperation inputs on game applications from a single radiogame-controller 25 or a plurality of radio game-controllers 25, andconveys them to the first parameter processing unit 44. The firstparameter processing unit 44 supplies information on the number ofcontrollers participating on a communication or game, instructions fromthe controller and the like, to the application processing unit 18 viathe control unit 16. The application processing unit 18 shown in FIG. 1executes game applications, based on the received operation inputs. Theoutput unit 20 shown in FIG. 1 is comprised of a display unit, a speakerand so forth, and a processing result by the application processing unit18 is outputted to this output unit 20. The operational state notifyingunit 48 sends BT_Active indicative of a communication execution state inthe first wireless communication module 12, to the second wirelesscommunication module 14. BT_Active is a pulse signal by which to stopforcibly the communication by the second wireless communication module14 if it goes high. The synchronous signal notifying unit 62 sendsBT_Sync to the second wireless communication module 14. BT_Sync is asignal generated based on “pulse information indicative of start timingof a communication cycle” which is a parameter notified from the controlunit 16. BT_Sync may be risen up with a timing, by a predeterminedperiod, prior to the timing at the beginning of a communication cycle.In the periodic communication mode, BT_Sync alone is taken intoconsideration in the second wireless communication module 14.

FIG. 4 illustrates an constitutional example of the second wirelesscommunication module 14 shown in FIG. 1. The second wirelesscommunication module 14 includes a second parameter processing unit 40and a second transceiver 42. The second transceiver 42 receives therespective status information from a single mobile game machine 30 or aplurality of mobile game machines 30. The second transceiver 42 alsotransfers the information sent from the control unit 16, to mobile gamemachines 30 participating in the WLAN. As a result, a game applicationreflecting the status information on the other mobile game machines 30is executed in the game apparatus 10, so that a plurality of users canenjoy simultaneously the game by the respective mobile game machines 30.When a mobile game machine 30 is used as a game controller, the secondparameter processing unit 40 in the second wireless communication module14 supplies the operation inputs from the mobile game machine 30 to theapplication processing unit 18 via the control unit 16, similarly to thefirst parameter processing unit 44 in the first wireless communicationmodule 12. When a mobile game machine 30 is used as a terminal for usewith moving images, the second transceiver 42 delivers moving image datato the mobile game machine 30. The second transceiver 42 transmits toand receives from the PC 32 such data as the moving images.

Now, an operation in the periodic communication mode will be describedin detail. FIGS. 5A to FIG. 5D is a timing chart showing examples of thestates of communication when the periodic communication mode isselected. FIG. 5A shows a state of communication between a firstwireless communication module 12 and a radio game-controller 25. FIG. 5Bshows a state of communication by a second wireless communication module14. FIG. 5C shows a period in which a communication between a secondwireless communication module 14 and a mobile game machine 30 or PC 32under the control thereof is to be suppressed. FIG. 5D shows an exampleof a state of transmission of BT_Sync transmitted from a first wirelesscommunication module 12 to a second wireless communication module 14. Itis assumed here in the timing chart shown in FIGS. 5A to 5D that thecommunication cycle of the first wireless communication module 12 andthe second wireless communication module 14 is set to one time (1×) thereference communication cycle. The horizontal axes shown in FIGS. 5A to5D indicate the time (t) axes. The start time of communications by thefirst wireless communication module 12 and the second wirelessconnection module 14 is identical to the start time of communicationcycles of the respective modules 12 and 14. Thus, when the communicationcycles of the respective modules 12 and 14 start, the communications bythe respective modules 12 and 14 also start.

Assume in the timing chart shown in FIGS. 5A to 5D that “modeinformation” set by the control unit 16 to the second wirelesscommunication module 14 is the periodic communication mode. The“communication cycle” is set as one time (1×) the referencecommunication cycle. In FIGS. 5A to 5D, the respective communicationcycles are t₀ to t₂, t₂ to t₄ and so forth. As “communication prohibitedperiods”, t₀ to t₁ (first communication prohibited period 100), t¹⁻³ tot₃ (second communication prohibited period 300 and first communicationprohibited period 400) and t₄ to t₅ (first communication prohibitedperiod 600). Based on BT_Sync notified from the first wirelesscommunication module 12, the second wireless communication module 14autonomously stops the execution of communication by itself in thecommunication prohibited periods including the first communicationprohibited period 100, second communication period 300, firstcommunication prohibited period 400 and first communication prohibitedperiod 600 conveyed from the control unit 16. The second wirelesscommunication module 14 sends CTS to the mobile game machine 30 and PC32 under the control thereof so as to stop the execution ofcommunication by them to the second wireless communication module 14.Here, a period, such as t₁ to t¹⁻³, during which the second wirelesscommunication module 14 is capable of executing a communication iscalled an unprotected (page scan) interval or an unprotectedcommunication period. In an unprotected communication period 200 or anunprotected communication period 500, the communication by the firstwireless communication module 12 is not protected. Hence, even if thepage scan for searching a newly participating radio game-controller 25is performed, it is unlikely to succeed because the communication by thesecond wireless communication module 14 is present. If a secondcommunication prohibited period exists as a communication suppressioninterval in the last half of a communication cycle, a period such ast¹⁻³ to t₂ (second communication prohibited period 300) will beparticularly called a protected (page scan) interval or a protectedcommunication period. “Cycle for communication prohibited period” is setto “2”. That is, the protected communication period is set once everytwo communication cycles. More specifically, in the communication cycleof t₀ to t₁, the period of t¹⁻³ to t₃ is set as a protectedcommunication period, namely, the second communication prohibited period300. On the other hand, in the communication cycle of t₂ to t₄, theprotected communication period is not set.

First, the first wireless communication module 12 starts a communicationwith three radio game-controllers 25 at time t₀. It is preferred thatthe communication between the first wireless communication module 12 andthe radio game-controller 25 be performed in a bursty manner andterminated within a short period of time. The first wirelesscommunication module 12 performs polling in sequence with the threeradio game-controllers 25, respectively. At each time, the firstwireless communication module 12 receives data from the radiogame-controller 25. The number of the first wireless communicationmodules 12 in use is only exemplary here, and one to seven radiogame-controllers can be managed by the first wireless communicationmodule 12.

The first wireless communication module 12 notifies the second wirelesscommunication module 14 that the communication be started at time t₀,and at the same time notifies it of BT_Sync by the communication timingsetting unit 58. As a result thereof, the second wireless communicationmodule 14 can obtain time at which a communication starts, namely, TBTT(Target Beacon

Transmission Time), and can operate semiautonomously. In this example,the communication prohibited time is set to t₀ to t₁. It is to be notedthat the first communication prohibited period in t₂ to t₃ and t₄ to t₅may be identical to the length of t₀ to t₁. From the start timing ofeach communication cycle until the end time of the first communicationprohibited interval, the first wireless communication module 12 canperform communication with the radio game-controller 25 without beingaffected from the communication by the second wireless module or WLAN.As shown in FIG. 5A, even in intervals other than the firstcommunication prohibited interval, the first wireless communicationmodule 12 may continue the page scan. By so doing, a communication withthe radio game-controller 25 can be executed in an interval, forexample, from t₁ until t¹⁻¹ during which the second wirelesscommunication module 14 is not communicating (that is, the secondwireless communication module 14 is not active). In another words, auser will enjoy more comfort by using the first wireless communicationmodule 12 whenever the first wireless communication module 12 tries tocommunicate with the radio game-controller 25 in any period.

When the second wireless module 14 receives BT_Sync and notification ofcommunication prohibited time, it stands by during a period of a firstcommunication prohibited period from time t₀ to t₁ and further stands byfor a period of random waiting time called “back-off” thereafter andthen sends a beacon signal. The start time of communication may berepresented as relative time from the notification time. The waiting isachieved in a manner such that the second wireless communication module14 notifies the mobile game machine 30 and PC 32 under the controlthereof, of a CTS. A CTS packet includes at least timing and durationfor communication stoppage. The mobile game machine 30 notified of theCTS packet stops the communication until the timing with which acommunication stays inactive terminates. The second communication module14 itself stops the execution of communication autonomously.

After the first communication prohibited period has passed (t₁, t₃ andt₅), the second wireless communication module 14 communicates with acommunication party to be communicated with a high priority, in a periodof time other than the communication prohibited period set by thecontrol unit 16, and then communicates with communication parties otherthan said communication party. “A communication party to be communicatedwith a high priority” includes a communication apparatus such as amobile game machine 30. Hence, if the communication prohibited period isset by a CTS for a long period of time, namely, if a protectedcommunication period is set for a longer period of time, thecommunication time with a PC 32 and the like will be short. However,since in most cases the degree of instant response required, namely, thedegree of real-timeliness required is low with the PC 32 compared withthe mobile game machine 30 and the like, no problem will arise in thepractical operation.

More specifically, in order to perform communication with a mobile gamemachine 30, deemed to have a high priority, which is to serve as a gamecontroller that gives instructions to a game apparatus 10, the secondwireless communication module 14 sends out a beacon signal. Upon receiptof the beacon signal, the mobile game machine 30 which operates under acontrol of the second wireless communication module 14 transmits statusinformation on the respective games. Referring to FIG. 5B, the secondwireless communication module 14 is allowed to communicate with themobile game machine 30 until t¹⁻¹. The second wireless communicationmodule 14 is also allowed to communicate with a PC 32 during a period oftime from t¹⁻¹ until t¹⁻². As shown in FIG. 5C, by the timing t¹⁻³ whena protected communication period starts, the second wirelesscommunication module 14 conveys the CTS to the mobile game machine 30and PC 32 under the control thereof. The CTS in such a case isinformation that contains communication prohibited periods in both thesecond communication prohibited period 300 and the first communicationprohibited period 400 for the next communication period that follows theperiod 300. When this CTS is conveyed accordingly, the communicationexecution in the first wireless communication module 12 is reliablysecured also in the period 400 for the next communication period thatfollows the second communication prohibited period 300. As describedearlier, no protected communication period exists in a communicationcycle from t₃ to t₄, so that the second wireless communication module 14may convey the CTS to the mobile game machine 30 under the controlthereof at t₄ which is the end timing of a communication cycle.

Prior to the start timing of the communication prohibited period set bythe control unit 16, the second wireless communication module 14 maytransmit to communication parties such as a mobile game machine 30executing a communication with said second wireless communication module14, a NAV (Network Allocation Vector) by which to request theprohibition of said communication, instead of CTS. By employing thisarrangement, the communication jamming in the first wirelesscommunication module 12 caused by signals transmitted from the mobilegame machine 30 and the like can be prevented. For instance, ifequipment that possibly restricts a communication can be identified, aperiod to restrict a PC 32 may be set, by a NAV, as the sum of the firstcommunication period and the second communication period. Thereby, theinterference, caused by the PC 32, of communication between the firstwireless communication module 12 and the radio game-controller 25 and ofcommunication between the second wireless communication module 14 andthe mobile game machine 30 can be avoided. As a result, thecommunication in the communication system 1 can be more stabilized.

According to the above-described embodiment, the communication timingsetting unit 58 sets the first communication prohibited time betweenfrom the communication start time of the first wireless communicationmodule 12 until that of the second wireless communication module 14,based on a monitored result of communication load of the first wirelesscommunication module 12. As another example, it is possible that thecommunication timing setting unit 58 sets the first communicationprohibited period between from the communication start time of thesecond wireless communication module 14 until that of the firstcommunication module 12, based on a monitored result of communicationload of the second wireless communication module 14. For example, if thefirst wireless communication module 12 starts during execution of acommunication by the second wireless communication module 14, a firstcommunication prohibited period by reference to the communication starttime of the second wireless communication module 12 may be set. In thiscase, too, the accurate time management can be facilitated by setting afirst communication prohibited period by reference to the communicationstart time of the first wireless communication module 12 as will bedescribed later.

The first wireless communication module 12 and the second wirelesscommunication module 14 may operate on a common clock. For example, theclock may be supplied to the communication modules 12 and 14,respectively, from the clock unit 60 in the control unit 16. The clockused in either one of the first wireless communication module 12 and thesecond wireless communication module 14 may be supplied to the other. Ifa high-speed clock is employed in either the first wirelesscommunication module 12 or the second wireless communication module 14,the use of this scheme will be desirable. Since the first wirelesscommunication module 12 can transmit to and receive from the radiogame-controller 25 the data in a bursty manner under an accurate timecontrol, the time management for the communication of the first wirelesscommunication module 12 is achieved relatively easily. Hence, it ispreferred that a clock be put to a common use between the first wirelesscommunication module 12 and the second wireless communication module 14by supplying the clock used in the first wireless communication module12 to the second wireless communication module 14. If the first wirelesscommunication module 12 and the second wireless communication module 14are integrally structured, clocks may be supplied from a clock unitwhich is commonly provided. By sharing the same clocks, the both modules12 and 14 can be easily synchronized.

According to the present embodiment, the communication cycles for thefirst wireless communication module 12 and the second wirelesscommunication module 14 are set to integral multiples of a referencecommunication cycle, respectively. Therefore, the first communicationprohibited time between from the communication start time of the firstwireless communication module 12 until that of the second wirelesscommunication module 14 can be fixed. As a result, it is only necessarythat the offset time be conveyed to the second wireless communicationmodule 14 only once. Thereafter, the respective communication modulesuse the common clock, so that the stable communication can be performed,without mutual interference, based on the communication cycles setrespectively.

The first wireless communication module 12 and the second wirelesscommunication module 14 may operate on their own independent clocks,respectively. For example, if the first wireless communication module 12and the second wireless communication module 14 are made by differentmanufactures, the respective communication modules will operate on theirown clocks. Hence, it is difficult to achieve the exact synchronizationtherebetween. As a result, the first wireless communication module 12may convey to the second wireless communication module 14 the BT_Syncindicated as the communication start timing of the first wirelesscommunication module 12 on a periodic basis so as to align thesynchronization. Even if the respective modules employ their ownindependent clocks, the actual difference between the clocks will beextremely small. Thus, adjusting the operation timing of the secondwireless communication module 14 on a periodic basis makes it possibleto maintain the state in which the first communication period of thefirst wireless communication module 12 does not overlap with the secondcommunication period of the second wireless communication module 14.

As discussed earlier, the first communication prohibited time is set inaccordance with the time at which the communication in the firstwireless communication module 12 has been all completed. Since the firstwireless communication module 12 performs communication using Bluetoothprotocols, the communication can be executed in a more bursty mannerthan using the IEEE802.11 protocols employed in the CSMA/CA scheme.Since the first communication prohibited period is set by using thestart time of the first wireless communication module 12 as a reference,the free time between the communication end time of the first wirelesscommunication module 12 and the communication start time of the secondwireless communication module 14 can be reduced. With reference to anexample shown in FIGS. 5A to 5D, there is provide a little time marginbetween after the communication by the first wireless module 12 has beencompleted until a beacon is transmitted by the second wirelesscommunication module 14. It is also possible that the communicationcycle of the second wireless communication module 14 is startedimmediately after the completion of communication by the first wirelesscommunication module 12 by setting the time interval from thecommunication start of the first wireless communication module 12 untilthe end thereof equal to the first communication prohibited time andthen a beacon signal is transmitted from the second wirelesscommunication module 14. On the other hand, the communication timingsetting unit 58 may set the first communication prohibited time in amanner such that the time necessary for searching a radiogame-controller 25 which establishes a new wireless connection with thefirst wireless communication module 12 is added up with the time atwhich the communication in the first wireless communication module 12has all been completed. This search time may always be included in thefirst communication prohibited time. Also, if the search frequency is tobe reduced, the search time may be periodically included in the firstcommunication prohibited time.

Since there is configured a dynamic wireless network in thecommunication system 1, not only a case where a new radiogame-controller 25 participates in a piconet but also a case where analready participating radio game-controller 25 withdraws from thepiconet is possible. In the control unit 16, the communication loadmonitoring unit 54 may monitor the change in number of radiogame-controllers 25 and the communication timing setting unit 58 mayreset a first communication prohibited time and/or a communication cycleaccording to the monitored result. The same is true of a case where anew mobile game machine 30 participates in a wireless LAN or an alreadyparticipating mobile game machine 30 withdraws from the wireless LAN.That is, the communication timing setting unit 58 may reset thecommunication cycle according to the monitored result obtained by thecommunication load monitoring unit 54.

FIGS. 6A and 6B is a timing chart showing a modification of thecommunication state when a periodic communication mode is selected. FIG.6A shows a state of communication between the first wirelesscommunication module 12 and the radio game-controller 25. FIG. 6B showsa state of communication between the second wireless communicationmodule 14 and the mobile game machine 30. The states of communicationbetween the second wireless communication module 14 and the PC 32 areomitted in FIGS. 6A and 6B. Similar to FIGS. 5A to 5D, protectedcommunication periods may be provided.

In the timing chart shown in FIGS. 6A and 6B, the communication periodfor the first wireless communication module 12 and the second wirelesscommunication module 14 is set to double the reference communicationcycle. This are the timing chart where no low-delay or minimum-delay isrequired, and it is assumed herein that a large amount of data istransmitted between the second wireless communication module 14 and themobile game machine 30. As discussed before, when the communicationcycle of the first wireless communication module 12 is set longer, thesecond communication cycle of the second wireless communication module14 can be set longer. During this second communication period, HCCA(Hybrid Coordination Function Controlled Channel Access) that guaranteesthe quality can be executed by a central control using the polling bythe second wireless communication module 14.

In HCCA, the second wireless communication module 14 performs schedulingwhere a high priority is considered or placed on the mobile game machine30, and the second wireless communication module 14 sends a pollingframe describing a channel use time that grants a transmission. Duringthe transmission by the mobile game machine 30 in which the transmissionis granted, access from other mobile game machines 30 is restricted andthe QoS can be guaranteed. Although the above is for the case where nolow-delay is required of the communication by the radio game-controller25, the communication cycle of the second wireless communication module14 may be set longer even in a case where no low-delay is required of acommunication by the mobile game machine 30. For example, when thelow-delay is required of the communication by the radio game-controller25 whereas no low-delay is required of the communication by the mobilegame machine 30, the communication cycle of the first wirelesscommunication module 12 is set to a reference communication cyclewhereas that of the second wireless communication module 14 is set todouble the reference communication cycle. The power consumed by theradio game-controller 25 and the mobile game machine 30 can be kept lowby reducing the ratio of a communication period to a communicationcycle.

FIGS. 7A and 7B is a timing chart showing an example of thecommunication state when a non-periodic communication mode is selected.FIG. 7A shows a state of communication between the first wirelesscommunication module 12 and the radio game-controller 25. FIG. 7B showsan example of an interval where the communication by the second wirelesscommunication module 14 is prohibited. The states of communicationbetween the second wireless communication module 14 and the PC 32 areomitted in FIGS. 7A and 7B.

Here, the non-periodic communication mode or non-periodic mode is a modefor avoiding mutual interference between WLAN communication andBluetooth communication, in which the communication by the firstwireless communication module 12 is executed on a non-periodic basis.The non-periodic communication mode is mainly used, by Bluetooth, foraudio communication. This is because since the audio communication isperformed on a non-periodic basis and therefore the periodic control israther difficult to achieve. When a user uses a PC 32, the non-periodiccommunication mode may also be used with the game apparatus 10 being notpowered on. That is, normally, the only WLAN protocols in the secondwireless communication module 14 are used, and the Bluetooth protocolsare used if needed. This is because it is difficult to predict inadvance the execution of audio communication by a user and the operationof the radio game-controller 25 in a case when the user starts a game.Thus, as the need arises, the first wireless communication module 12executes a communication with the radio game-controller 25, and whilethe radio game-controller 25 is in communication, the second wirelesscommunication module 14 semiautonomously stops temporarily thecommunication with the PC 32 in the light of the state of communicationin the first wireless communication module 12.

More specifically, when the first wireless communication module 12executes communication with the radio game-controller 25, the firstwireless communication module 12 transmits beforehand a signalindicative of a communication start request (hereinafter referred to as“BT_Active”), not BT_Sync, to the second wireless communication module14. While BT_Active is high, the second wireless communication module 14has only to stop the execution of communication. Also, the aboveprocessing may be performed via the control unit 16. In this manner, thesecond wireless communication module 14 determines whether or not toexecute a communication in the light the state of communication in thefirst wireless communication module 12, so that the communication by theboth modules 12 and 14 can be conducted without interference. As aresult, the communication time by the first wireless module 12 can bereliably secured. Furthermore, the second wireless communication module14 can freely execute a communication as long as the first wirelesscommunication modules 12 is not in communication. Thus, the throughputas a whole system can be improved.

Here, if the non-periodic communication mode is selected, the firstwireless communication module 12 needs to properly avoid thecommunication in the second wireless communication 14 in order toexecute the non-periodic communication. Hence, prior to the start ofcommunication, the first wireless communication module 12 conveys asignal, by which to prohibit the execution of communication, to thesecond wireless communication module 14 in a predetermined period thatincludes at least a period during which said first wirelesscommunication module 12 is in communication. This notification of thesignal is made in an interval between t₀ and t₁, as illustrated in FIG.7A. The intervals t_(lead) and t_(tail) may be provided as waitingperiods to allow for the first wireless communication module 12 toproperly start and terminate a communication. This notification may alsobe made through the control unit 16. This arrangement according to thepresent embodiment may also be realized in a manner such that thecontrol unit 16 sends the notification to the both modules 12 and 14. Inany case, the second wireless communication module 14 stops thecommunication while a pulse shown in FIG. 7B stays high. In this manner,the second wireless communication module 14 determines whether or not toconduct a communication in the light of the state of communication inthe first wireless communication module 12, so that the communication bythe both modules 12 and 14 can be executed without interference.

When controlling the communication functions in the first wirelesscommunication module 12 and the second wireless communication 14, thecontrol unit 16 according to the present embodiment may control thefirst wireless module 12 and the second wireless communication module 14in accordance with a mode selected from a plurality of modes to avoidthe mutual interference caused between the WLAN communication and theBluetooth communication. The plurality of modes to avoid the mutualinterference caused between the WLAN communication and the Bluetoothcommunication may include, at least, a periodic communication mode, anon-periodic communication mode, a free-run mode and a full-timesuppression mode. The free-run mode is a mode in which the secondwireless module 14 constantly executes the communication without evernegotiating it with the first wireless communication module 12 inadvance. In this mode, the first wireless communication module 12 mayalso be able to execute a communication by implementing theaforementioned AFH. The full-time suppression mode is a mode to secureconstantly the execution of a communication by a first wirelesscommunication module 12, and this is accomplished when the control unit16 forcibly prohibits the second wireless communication module 14 fromexecuting the communication. The full-time suppression mode is a modewhich is usually used at the time of negotiation for establishing acommunication when the Bluetooth protocol starts the communication withthe radio game-controller 25. In this full-time suppression mode, theexecution of a communication by the WLAN protocol is completely stopped.If the communication by the second wireless communication module 14 isprohibited, it goes without saying that the communication by the mobilegame machine 30 and PC 32 under the control thereof will be prohibited,too.

The present invention has been described based on the embodiments whichare only exemplary. It is therefore understood by those skilled in theart that other various modifications to the combination of eachcomponent and process are possible and that such modifications are alsowithin the scope of the present invention. In FIG. 1, the first wirelesscommunication module 12 and the second wireless communication module 14have their respective antennas. However, the antennas may be put to acommon use. Since the communication periods for the first wirelesscommunication modules 12 and those for the second wireless communicationmodule 14 are assigned in such a manner as not to overlap one another,it is possible to commoditize the antennas.

In the above-described embodiments, the mobile game machine 30 in thecommunication system of FIG. 1 is in communication with the secondwireless communication module 14 using the IEEE802.11 protocol. Themobile game machine 30 may further function as a Bluetooth master andtherefore may communicate with other Bluetooth terminal apparatuses. Insuch a case, the mobile game machine 30 may be equipped with the samecommunication functions as with the game apparatus 10, and it ispreferred that a communication with a Bluetooth terminal apparatus beexecuted during a communication period assigned between a communicationperiod for the first wireless communication module 12 and that for thesecond wireless communication module 14.

In the present embodiments, the reference communication cycle is set to11.25 msec which is shorter than the frame rate (1/60 sec) of movingimages. The first wireless communication module 12 receives the user'soperation inputs from the radio game-controller 25 or mobile gamemachine 30 with a communication cycle which is an integral multiple ofthis reference communication cycle. The control unit 16 may sequentiallystore input signals received by the first wireless communication module12 in a buffer memory (not shown). The control unit 16 may read out theinput signals stored in the memory to the application processing unit18, in the cycle of frame rate for moving images.

If the communication cycle is 11.25 msec, there will be cases where thecontrol unit 16 receives the input signals twice from the same gamecontroller during a period of the frame rate (1/60 sec). At that time,the control unit 16 may read out only the most current input signalreceived to the application processing unit 18. In this case, the buffermemory in the control unit 16 is structured as an overwrite-type memory,so that the input signals received by the first wireless communicationmodule 12 are overwritten sequentially. As a result, the most currentinput signals are stored in the buffer memory.

The control unit 16 may add up the two input signals stored in a memoryand then read out the summation result to the application processingunit 18. For instance, if the first input signal is an indicator signalthat indicates to move a character to the right and the next signal isan indicator signal to move the character to the right, the control unit16 supplies to the application processing unit 18 an indicator signalindicating to move the character to the right twice. For instance, ifthe first input signal is an indicator signal that indicates to move acharacter to the right and the next signal is an indicator signal tomove the character to the up position, the control unit 16 supplies tothe application processing unit 18 an indicator signal indicating tomove the character to the right once and move it to the up once. In thecommunication system 1 according to the present embodiments, thecommunication cycle and the frame rate are asynchronous to each other.However, when the control unit 16 processes the input signals in thesame manner as described above, the operation inputs can be properlyreflected on game applications. Though the description has been given ofthe processing of the input signals received by the first wirelesscommunication module 12, the control unit 16 also performs a similarprocessing on the input signals received by the second wirelesscommunication module 14.

Also, the information can be transmitted from the game apparatus 10 tothe game controllers. As an example, it is conceivable that controlinformation with which to vibrate the game controllers is transmittedaccording to the progress of a game. It is preferred then that thevibrating information be constantly transmitted to intervals to bevibrated. A structure may be such that a wired controller forcontrolling the game apparatus 10 by wire communication is provided,control information for starting the vibration is transmitted at thetime of starting the vibration and control information for terminatingthe vibration is transmitted at the time of terminating the vibration.With this structure having the wire communication, the load of controlunit 16 can be reduced by reducing the number of transmissions of thecontrol information.

While the preferred embodiments of the present invention have beendescribed using specific terms, such description including objectivesand applications is for illustrative purposes only, and it is to beunderstood that other changes and variations may be made withoutdeparting from the spirit or scope of the appended claims.

What is claimed is:
 1. A communication terminal apparatus, comprising: afirst wireless communication module which executes communication in apredetermined frequency band, using a first communication scheme; asecond wireless communication module which executes communication in thepredetermined band, using a second communication scheme that differsfrom the first communication scheme; and a control unit which selectsone of a plurality of communication modes, including a periodicalcommunication mode in which said first wireless communication module andsaid second wireless communication module execute communication inaccordance with a reference communication cycle common thereto, and anon-periodic communication mode in which said first wirelesscommunication module executes communication on a non-periodic basis. 2.The communication terminal apparatus according to claim 1, wherein thecontrol unit sets mode information for identifying a communication modefor said first wireless communication module and said second wirelesscommunication module.
 3. The communication terminal apparatus accordingto claim 1, wherein said first wireless communication module conveys astart timing in a communication cycle of said first wirelesscommunication module to said second wireless communication module. 4.The communication terminal apparatus according to claim 3, wherein saidsecond wireless communication module determines a start timing of aprohibited communication period of said second wireless communicationmodule based on the conveyed start timing in the communication cycle ofsaid first wireless communication module.
 5. The communication terminalapparatus according to claim 3, wherein said first wirelesscommunication module sends a status signal indicating a status ofexecution of communication in said first wireless communication moduleto said second wireless communication module.
 6. The communicationterminal apparatus according to claim 5, wherein, when the status signalindicates that said first wireless communication module executescommunication in the non-periodic communication mode, said secondwireless communication module stops communication.
 7. The communicationterminal apparatus according to claim 5, wherein, in the periodiccommunication mode, said second wireless communication module executescommunication using the conveyed start timing in the communication cycleof said first wireless communication module, regardless of the statussignal.
 8. The communication terminal apparatus according to claim 1,wherein the periodic communication mode is a communication mode selectedwhile a game is being executed and the non-periodic communication modeis a communication mode selected while audio communication is beingexecuted.
 9. A method for controlling communications of a first wirelesscommunication module which executes communication in a predeterminedfrequency band, using a first communication scheme, and a secondwireless communication module which executes communication in thepredetermined band, using a second communication scheme differing fromthe first communication scheme, the method including: selecting one of aplurality of communication modes, including a periodical communicationmode in which said first wireless communication module and said secondwireless communication module execute communication in accordance with areference communication cycle common thereto, and a non-periodiccommunication mode in which said first wireless communication moduleexecutes communication on a non-periodic basis; and controlling theexecution of communication in said first wireless communication moduleand said second wireless communication module in accordance with theselected communication mode.
 10. A computer program embedded on anon-transitory computer readable recording medium and implementing, on acomputer for controlling communications of a first wirelesscommunication module which executes communication in a predeterminedfrequency band, using a first communication scheme, and a secondwireless communication module which executes communication in thepredetermined band, using a second communication scheme differing fromthe first communication scheme, the modules comprising: a moduleconfigured to select one of a plurality of communication modes,including a periodical communication mode in which said first wirelesscommunication module and said second wireless communication moduleexecute communication in accordance with a reference communication cyclecommon thereto, and a non-periodic communication mode in which saidfirst wireless communication module executes communication on anon-periodic basis; and a module to control the execution ofcommunication in said first wireless communication module and saidsecond wireless communication module control in accordance with theselected communication mode.
 11. The computer readable recording mediumhaving embedded thereon the program according to claim 10.